Kraus
multiplex channel simulator

ABSTRACT

THIS INVENTION IS A METHOD OF OPERATING A COMPUTER TO MODEL AN IBM SYSTEM/360 MULTIPLEX CHANNEL IN SUCH GREAT DETAIL THAT THE TIMING RELATIONSHIPS OF EVENTS IN A REAL CHANNEL ARE SUBSTANTIALLY MAINTAINED IN THE SIMULATED CHANNEL, THUS PROVIDING A METHOD THROUGH WHICH THE SIMULATED CHANNEL APPEARS TO SIMULATED CONTROL UNIT EQUIPMENT MUCH THE SAME AS A REAL CHANNEL WOULD APPEAR TO REAL CONTROL UNIT EQUIPMENT, AND ALSO SO THAT THE SIMULATED EQUIPMENT APPEARS TO THE CONTROL COMPUTER MUCH THE SAME AS REAL EQUIPMENT. WITH THIS METHOD, NEW EQUIPMENT TO BE USED ON AN EXISTING SYSTEM/360 COMPUTER, CAN BE SIMULATED IN ORDER TO ASCERTAIN THE EFFECT OF THE NEW EQUIPMENT ON THE EFFICIENCY OF THE COMPUTER. ALSO, WITH THIS METHOD, NEW OR REWRITTEN PROGRAMS FOR USE ON YET TO BE INSTALLED EQUIPMENT CAN BE DEBUGGED PRIOR TO ACTUAL INSTALLATION BY DRIVING THE NEW PROGRAMS OVER THE SIMULATED CHANNEL.   THE METHOD IS COMPRISED OF THE STEPS OF INTERCEPTING START I/O (SIO) OPERATIONS, DETERMINING IF THEY ARE FOR A SIMULATED DEVICE, IF SO, PASSING THE ADDRESS OF THE CHANNEL PROGRAM TO THE CHANNEL MODELLING PROCEDURE, NEXT INSPECTING THE FIRST CHANNEL COMMAND WORD (CCW) AS TO KEY, ADDRESS OF THE CCW, THE COMMAND CODE, PRESENCE   OF A TRANSFER-IN-CHANNEL (TIC), THE CCW FORMAT AND THE CCW DATA ADDRESS. IF AN INVALID CONDITION IS FOUND, SETTING APPROPRIATE CHANNEL STATUS WORD (CSW) BITS AND THE CONDITION CODE FOR RETURNING TO THE OPERATING SYSTEM. IF VALID, CHECKING THE PROGRAM CONTROLLED INTERRUPT (PCI) FLAG, OBTAINING A TIME ESTIMATE OF WHAT REAL EQUIPMENT MIGHT USE TO EXECUTE THE CCW, PLACING THAT TIME ON A CHAIN OF FUTURE EVENTS, CAUSING AN INTERRUPT WHEN THAT TIME EXPIRES, TRANSFERRING THE DATA DESIGNATED BY THE CCW, AND DETERMINING IF DATA OR COMMAND CHANGING IS IN EFFECT. IF NOT, SETTING UP A CSW AND RETURNING TO THE OPERATING SYSTEM. IF SO, PERFORMING VALIDITY CHECKS ON THE NEXT CCW, CALCULATING ITS ESTIMATED TIME OF EXECUTION, PLACING THAT TIME ON A FUTURE EVENTS CHAIN, AND CONTINUING UNTIL THE CHANNEL PROGRAM IS ENDED OR UNTIL AN ERROR INTERVANES.

' DEFENSIVE PUBLICATION UNITED STATES PATENT OFFICE Published at the request of the applicant or owner in accordance with the Notice of Dec. 16, 1969, 869 0.6. 687. The abstracts of Defensive Publication applications are identified by distinctly numbered series and are arranged chronologically. The heading of each abstract indicates the number of pages of specification, including claims and sheets of drawings contained in the application as originally filed. The files of these applications are available to the public for inspection and reproduction may be purchased for 30 cents a sheet.

Defensive Publication applications have not been examined as to the merits of alleged invention. The Patent Oihce makes no assertion as to the novelty of the disclosed subject matter.

PUBLISHED MARCH 5, 1974 T920,014 MULTIPLEX CHANNEL SIMULATOR Joanne Kraus, Staatsburg, N.Y., assignor to International Business Machines Corporation, Armonk, N.Y. Continuation of abandoned application Ser. No. 284,844, Aug. 30, 1972. This application July 19, 1973, Ser. No. 380,930

Int. Cl. G06f 9/12 US. Cl. 444-1 6 Sheets Drawing. 18 Pages Specification TURN on I m PROTECTION error I SET common BIT m csw con: mi smus BYIES TURN ON PRDGRAN CHECK BIT IN CSVI STATUS BITES v "5 "4 I5 "'I ET A non SET UP A riiii ius G TIMER EVENT OF FREE 3mg m A *EVEIIT 0N TIIE "(9 CORE m mgm up TIIIEIT OIIAITI This invention is a method of operating a computer to model an IBM System/360 multiplex channel in such great detail that the timing relationships of events in a real channel are substantially maintained in the simulated channel, thus providing a method through which the simulated channel appears to simulated control unit equipment much the same as a real channel would appear to real control unit equipment, and also so that the simulated equipment appears to the control computer much the same as real equipment. With this method, new equipment to be used on an existing System/ 3 60 computer, can be simulated in order to ascertain the effect of the new equipment on the efliciency of the computer. Also, with this method, new or rewritten programs for use on yet to be installed equipment can be debugged prior to actual installation by driving the new programs over the simulated channel.

@ arr A moi or FREE con:

PUT RETURN POINT INFXTINR) 1N TINEN EVENT RLUBIT GET ADDRESS INDICATE FIRST ANALYS1$- CONTROL UNIT 0} g" m mos EVENT on me mm (D cum I23 \IZZ muss CORE use on TIMER EVENT BLOCK cusIM AII/ILYZE cow ,150 AND uovr um WIS cow um CIIAINED YES 140 15s with Y SIGNAL CIISlII aroma SET PRUGRIJI CHECK BIT IN CST! B GET LOCK RETURN TO INTERCEPTUR The method is comprised of the steps of intercepting Start 1/0 (810) operations, determining if they are for March 5, KRAUS MULTIPLEX CHANNEL S IMULATOR Original Filed Aug. 30, 1972 e Sheets-Sheet 1 1/0 ,10 DEVICE 1 1 CPU ,8 k 148 N C T 2 SYSTEM r/o t 5 l N CLOCK DEVICE L N E U L N I T I/O DEVICE MEMORY March 5, 1974 J KRAUS MULTIPLEX CHANNEL SIMULATOR Original Filed Au 30, 1972 6 Sheets-Sheet 2 FIG 2 MAIN STORE Os 18A PROBLEM PROGRAM 19A AREA INTERGEPTOR 20 MULTIPL EX OMAMMEL 2L SIMULATOR CONTROL UNIT 22 SlMULATOR SIMULATOR MESSAGE 24 SIMULATOR PROBLEM PROGRAM ARE March 5, 1974 J KRAUS T920,014

MULTIPLEX CHANNEL SIMULATOR Original Filed Aug. 30, 1972 6 Sheets-Sheet :5

FIG. 3A

TURN ON PROGRAM CHECK BIT m csw smus BYTES 106 THE COMMAND CODE INVALID OR A TIC THE CCW FORMAT INVALID IS CCW DATA ADDRESS INVALID I15 I14 115 T w SET UP A I PLANE THE GETA BLOCK TIMER EVENT SAVE THE 00W OF FREE BLOCK FOR A EVENT ON THE CORE p01 lNTERRUPT TIMER CHAIN MPX 1 y THE POI NO \QAC ON I YES MULTIPLEX CHANNEL SIMULATOR Original Filed Aug. 30, 1972 6 Sheets-Sheet 4 FIG. 35

GET A BLOCK 116 OF FREE coRE PUT RETuRM POINT (MPXTIMR) 117 M TIMER EVENT BLOCK 119 T I18 GET ADDRESS INDICATE 0F PROPER CONTROL UNIT E EW SIMULATOR CUSIM COMPUTE TIME 120 T0 ExEcuTE TREccw 121 RELEASE coRE E INT/ PLACE EvEMT (TD USED FOR TIMER CQNDIT'ON ON THE TTMER EVENT BLOCK CHAIN March 5, 1974 J KRAUS MULTIPLEX CHANNEL SIMULATOR Original Filed Aug. 30, 1972 6 Sheets-Sheet 5 FIG. 4 A 155 154 FIG. 4 B

MP T MR GET BLOCK v E.) OFjFREE 7 SET UP RETl RN 1 R Y CORE 05W |NTE CEPT GUSIM 155 ANALYZE ,150 AND MOVE YES SIGNAL cusm TOHALT THE OPERATION TICANAL ANALYZE COMMA March 5, 1974 J. KRAUS MULTIPLEX CHANNEL SIMULATOR Original Filed 1972 I 6 Sheets-Sheet 6 Fl G. 6 FIG 5 R MPXHIO I TICANAL R C U 5 M GET ADDRESS 200 ANALYZE /160 OF NEXT THE HIO c cw 161 SET PROGRAM GET CORE FOR CHECK BIT TIM-ER BLOCK lN csw r 165 202' SET UP INT IS Y 05w FOR PLACE EVENT NEW COMMAND INTERRUPT A no CHAIN NO SET com) 164 SAVE ADDR 204 CODE T0 1 OF NEW cow v SET UP 165 RETURN ALL ZERO c s w RETURN 

